Template:Short description Template:Pp-move Template:Redirect Template:Automatic taxobox The nuthatches (Template:IPAc-en) constitute a genus, Sitta, of small passerine birds belonging to the family Sittidae. Characterised by large heads, short tails, and powerful bills and feet, nuthatches advertise their territory using loud, simple songs. Most species exhibit grey or bluish upper parts and a black eye stripe.
Most nuthatches breed in the temperate or montane woodlands of the Northern Hemisphere, although two species have adapted to rocky habitats in the warmer and drier regions of Eurasia. However, the greatest diversity is in Southern Asia, and similarities between the species have made it difficult to identify distinct species. All members of this genus nest in holes or crevices. Most species are non-migratory and live in their habitat year-round, although the North American red-breasted nuthatch migrates to warmer regions during the winter. A few nuthatch species have restricted ranges and face threats from deforestation.
Nuthatches are omnivorous, eating mostly insects, nuts, and seeds. They forage for insects hidden in or under bark by climbing along tree trunks and branches, sometimes upside-down. They forage within their territories when breeding, but they may join mixed feeding flocks at other times.
Their habit of wedging a large food item in a crevice and then hacking at it with their strong bills gives this group its English name.
TaxonomyEdit
Template:Phylogeny/Certhioidea The nuthatch family, Sittidae, was described by René-Primevère Lesson in 1828.<ref>Template:Cite book Lesson used the French Sittées rather than the Latin Sittidae.</ref><ref name = Cracraft/>
Sometimes the wallcreeper (Tichodroma muraria), which is restricted to the mountains of southern Eurasia, is placed in the same family as the nuthatches, but in a separate subfamily "Tichodromadinae", in which case the nuthatches are classified in the subfamily "Sittinae". However, the wallcreeper is more often placed in a separate family, the Tichodromadidae.<ref name=BWP>Snow & Perrins (1998) pp. 1408</ref>
The wallcreeper is intermediate in its morphology between the nuthatches and the treecreepers, but its appearance, the texture of its plumage, and the shape and pattern of its tail suggest that it is closer to the former taxon.<ref name="Vaurie">Template:Cite journal</ref>
The nuthatch vanga of Madagascar (formerly known as the coral-billed nuthatch) and the sittellas from Australia and New Guinea were once placed in the nuthatch family because of similarities in appearance and lifestyle, but they are not closely related. The resemblances arose via convergent evolution to fill an ecological niche.<ref name="HQfamily">Harrap & Quinn (1996) pp. 16–17 "Family Introduction"</ref> Template:Cladogram
The nuthatches' closest relatives, other than the wallcreeper, are the treecreepers, and the two (or three) families are sometimes placed in a larger grouping with the wrens and gnatcatchers. This superfamily, the Certhioidea, is proposed on phylogenetic studies using mitochondrial and nuclear DNA, and was created to cover a clade of (four or) five families removed from a larger grouping of passerine birds, the Sylvioidea.<ref name = Cracraft>Cracraft, J.; Barker, F. Keith; Braun, M. J.; Harshman, J.; Dyke, G.; Feinstein, J.; Stanley, S.; Cibois, A.; Schikler, P.; Beresford, P.; García-Moreno, J.; Sorenson, M. D.; Yuri, T.; Mindell. D. P. (2004) "Phylogenetic relationships among modern birds (Neornithes): Toward an avian tree of life." pp. 468–489 in Assembling the tree of life (J. Cracraft and M. J. Donoghue, eds.). Oxford University Press, New York. Template:ISBN</ref><ref>Template:Cite journal</ref>
Genus nameEdit
The nuthatches are all in the genus Sitta Linnaeus, 1758,<ref>Template:Cite book</ref> a name derived from Template:Linktext : Template:Transliteration, Ancient Greek for this bird.<ref name="Chambers">Template:Cite book</ref>
The English term nuthatch refers to the propensity of some species to wedge a large insect or seed in a crack and hack at it with their strong bills.<ref name="dict">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
Species boundariesEdit
Species boundaries in the nuthatches are difficult to define. The red-breasted nuthatch, Corsican nuthatch and Chinese nuthatch have breeding ranges separated by thousands of kilometres, but are similar in habitat preference, appearance and song. They were formerly considered to be one species, but are now normally split into three<ref name="HQlimits">Harrap & Quinn (1996) pp. 12–13 "Species limits"</ref> and comprise a superspecies along with the Krüper's and Algerian nuthatch. Unusually for nuthatches, all five species excavate their own nests.<ref name="Pasquet">Template:Cite journal</ref>
The Eurasian, chestnut-vented, Kashmir and chestnut-bellied nuthatches form another superspecies and replace each other geographically across Asia. They are currently considered to be four separate species, but the south Asian forms were once believed to be a subspecies of the Eurasian nuthatch.<ref name="HQeurasian">Harrap & Quinn (1996) pp. 109–114 "Eurasian Nuthatch"</ref> A recent change in this taxonomy is a split of the chestnut-bellied nuthatch into three species, namely the Indian nuthatch, Sitta castanea, found south of the Ganges, the Burmese nuthatch, Sitta neglecta, found in southeast Asia, and the chestnut-bellied nuthatch sensu stricto, S. cinnamoventris, which occurs in the Himalayas.<ref name="Rasmussen">Template:Cite book</ref> Mitochondrial DNA studies have demonstrated that the white-breasted northern subspecies of Eurasian nuthatch, S. (europea) arctica, is distinctive,<ref name="Zink">Template:Cite journal</ref> and also a possible candidate for full species status.<ref name="Dickinson"/> This split has been accepted by the British Ornithologists' Union.<ref name= sangster2012>Template:Cite journal</ref>
A 2006 review of Asian nuthatches suggested that there are still unresolved problems in nuthatch taxonomy and proposed splitting the genus Sitta. This suggestion would move the red- and yellow-billed south Asian species (velvet-fronted, yellow-billed and sulphur-billed nuthatches) to a new genus, create a third genus for the blue nuthatch, and possibly a fourth for the beautiful nuthatch.<ref name="Dickinson">Template:Cite journal</ref>
The fossil record for this group appears to be restricted to a foot bone of an early Miocene bird from Bavaria which has been identified as an extinct representative of the climbing Certhioidea, a clade comprising the treecreepers, wallcreeper and nuthatches. It has been described as Certhiops rummeli.<ref name="Manegold">Template:Cite journal</ref> Two fossil species have been described in the genus Sitta: S. cuvieri Gervais, 1852 and S. senogalliensis Portis, 1888, but they probably do not belong to nuthatches.<ref> Jiří Mlíkovský, Cenozoic Birds of the World. Part 1:Europe Template:Webarchive , Prague, Ninox Press, 2002, 407 p., p. 252, 273 </ref>
DescriptionEdit
Nuthatches are compact birds with short legs, compressed wings, and square 12-feathered tails. They have long, sturdy, pointed bills and strong toes with long claws. Nuthatches have blue-grey backs (violet-blue in some Asian species, which also have red or yellow bills) and white underparts, which are variably tinted with buff, orange, rufous or lilac. Although head markings vary between species, a long black eye stripe, with contrasting white supercilium, dark forehead and blackish cap is common. The sexes look similar, but may differ in underpart colouration, especially on the rear flanks and under the tail. Juveniles and first-year birds can be almost indistinguishable from adults.<ref name="HQfamily"/>
The sizes of nuthatches vary,<ref name="HQfamily"/> from the large giant nuthatch, at Template:Convert and Template:Convert,<ref name="HQgiant">Harrap & Quinn (1996) pp. 169–172 "Giant Nuthatch"</ref> to the small brown-headed nuthatch and the pygmy nuthatch, both around Template:Convert in length and about Template:Convert.<ref name="HQbhn">Harrap & Quinn (1996) pp. 130–133 "Brown-headed Nuthatch"</ref>
Nuthatches are very vocal, using an assortment of whistles, trills and calls. Their breeding songs tend to be simple and often identical to their contact calls but longer in duration.<ref name="HQfamily"/> The red-breasted nuthatch, which coexists with the black-capped chickadee throughout much of its range, is able to understand the latter species' calls. The chickadee has subtle call variations that communicate information about the size and risk of potential predators. Many birds recognise the simple alarm calls produced by other species, but the red-breasted nuthatch is able to interpret the chickadees' detailed variations and to respond appropriately.<ref name="Templeton">Template:Cite journal</ref>
SpeciesEdit
The species diversity for Sittidae is greatest in southern Asia (possibly the original home of this family), where about 15 species occur, but it has representatives across much of the Northern Hemisphere.<ref name="HQfamily"/> The currently recognised nuthatch species are tabulated below.<ref name=ioc2>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
| Species in taxonomic sequence | ||||
|---|---|---|---|---|
| Common and binomial names |
Image | Description | Range (population if known) | |
| White-cheeked nuthatch (Sitta leucopsis) |
File:White-cheeked Nuthatch (Sitta leucopsis) (39661424053) (cropped).jpg | Template:Convert long, white cheeks, chin, throat, and underparts, upper parts mostly dark grey. | western Himalayas<ref name="HQwcn">Harrap & Quinn (1996) pp. 148–150 "White-cheeked Nuthatch"</ref> | |
| Przevalski's nuthatch (Sitta przewalskii) |
File:Przevalski's nuthatch - Chengdong Wang (cropped).jpg | Template:Convert long, white cheeks, chin, throat, and underparts, upper parts mostly dark grey. | southeastern Tibet to western China<ref>Rasmussen, P.C., and J.C. Anderton. 2005. Birds of South Asia. The Ripley guide. Volume 2: attributes and status. Smithsonian Institution and Lynx Edicions, Washington D.C. and Barcelona</ref> | |
| Giant nuthatch (Sitta magna) |
File:Giant nuthatch (Sitta magna).jpg | Template:Convert long, greyish upper parts and whitish underparts. | China, Burma, and Thailand.<ref name="HQgiant" /> | |
| White-breasted nuthatch (Sitta carolinensis) |
File:Sitta-carolinensis-001.jpg | Template:Convert long, the white of the face completely surrounds the eye, face and the underparts are white, upper parts are mostly pale blue-grey. | North America from southern Canada to Mexico<ref name="HQwbn">Harrap & Quinn (1996) pp. 150–155 "White-breasted Nuthatch"</ref><ref>Bull, John and Farrand, John Jr. The Audubon Society Field Guide to North American Birds, Eastern Region. Alfred A. Knopf, Inc. (1977) pp. 646–647 "White-breasted Nuthatch"</ref> | |
| Beautiful nuthatch (Sitta formosa) |
File:Beautiful Nuthatch - Eaglenest - India (cropped).jpg | Template:Convert long, black-backed with white streaking, bright blue upper back, rump and shoulders, dull orange underparts and paler face. | Northeast India and Burma and locally in southern China and northern Southeast Asia<ref name="HQbeauty">Harrap & Quinn (1996) pp. 172–173 "Beautiful Nuthatch"</ref> | |
| Blue nuthatch (Sitta azurea) |
File:Blue Nuthatch - Cibodas Botanical Garden, Java, Indonesia (cropped).jpg | Template:Convert long, greyish upper parts and whitish underparts. | Malaysia, Sumatra and Java<ref name="HQbluen">Harrap & Quinn (1996) pp. 168–169 "Blue Nuthatch"</ref> | |
| Velvet-fronted nuthatch (Sitta frontalis) |
File:Velvet-fronted Nuthatch, Ganeshgudi, 26 FEB 2016, Vimal Rajyaguru,1 (cropped 2).jpg | Template:Convert long, violet-blue above, with lavender cheeks, beige underparts and a whitish throat, bill is red, black patch on forehead. | India and Sri Lanka through Southeast Asia to Indonesia<ref name="HQvfn">Harrap & Quinn (1996) pp. 161–164 "Velvet-fronted Nuthatch"</ref> | |
| Yellow-billed nuthatch (Sitta solangiae) |
File:SittaSolangiae.svg | Template:Convert long, white underparts, bluish upper parts, yellow beak. | Vietnam and Hainan Island, China<ref name="HQybn">Harrap & Quinn (1996) pp. 164–165 "Yellow-billed Nuthatch"</ref> | |
| Sulphur-billed nuthatch (Sitta oenochlamys) |
File:Sulfur-billed Nuthatch crop (cropped).jpg | Template:Convert long, pinkish underparts, yellow beak, bluish upper parts. | Endemic to the Philippines<ref name="HQsbn">Harrap & Quinn (1996) pp. 165–168 "Sulphur-billed Nuthatch"</ref> | |
| Pygmy nuthatch (Sitta pygmaea) |
File:Pygmy Nuthatch (Sitta pygmaea) at a feeder.jpg | Template:Convert long, grey cap, blue-grey upper parts, whitish underparts, whitish spot on the nape. | Western North America from British Columbia to southwest Mexico (2.3 million)<ref name="HQpigmy">Harrap & Quinn (1996) pp. 127–130 "Pygmy Nuthatch"</ref> | |
| Brown-headed nuthatch (Sitta pusilla) |
File:Brown-headed Nuthatch-27527-4c.jpg | Template:Convert long, brown cap with narrow black eye stripe and buff white cheeks, chin, and belly, wings are bluish-grey, small white spot at the nape of the neck. | Endemic to the Southeastern United States (1.5 million)<ref name="HQbhn" /> | |
| Bahama nuthatch
(Sitta insularis) |
Very similar to brown-headed nuthatch, but has a darker eye stripe, much longer beak, shorter wings, and a different call than it. | Endemic to Grand Bahama
(1–49 individuals, potentially extinct)<ref>{{#invoke:citation/CS1|citation |
CitationClass=web
}}</ref> | |
| Yunnan nuthatch (Sitta yunnanensis) |
File:Yunnan nuthatch.jpg | Template:Convert long, greyish upper parts and whitish underparts. | Endemic to southwest China<ref name="HQyunnan">Harrap & Quinn (1996) pp. 143–144 "Yunnan Nuthatch"</ref> | |
| Algerian nuthatch (Sitta ledanti) |
File:Sitta ledanti - Karim Haddad (cropped).jpeg | Template:Convert long, blue-grey above, and buff below. Male has a black crown and eye stripe separated by a white supercilium; female has a grey crown and eye stripe. | Endemic to northeast Algeria (Fewer than 1,000 pairs)<ref name="HQalgerian">Harrap & Quinn (1996) pp. 135–138 "Algerian Nuthatch"</ref> | |
| Krüper's nuthatch (Sitta krueperi) |
File:090503 Krupers nuthatch east of Gulf of Kalloni.jpg | Template:Convert long, whitish underparts with a reddish throat, mostly grey upper parts. | Turkey, Georgia, Russia and on the Greek island of Lesvos. (80,000–170,000 pairs)<ref name="HQkruper">Harrap & Quinn (1996) pp. 138–140 "Krüper's Nuthatch"</ref> | |
| Red-breasted nuthatch (Sitta canadensis) |
File:Red-breasted Nuthatch (Sitta canadensis)10-4c.jpg | Template:Convert long, blue-grey upper parts, with reddish underparts, white face with a black eye stripe, white throat, a straight grey bill and a black crown. | Western and northern temperate North America, winters across much of the US and southern Canada (18 million)<ref name="HQrbn">Harrap & Quinn (1996) pp. 144–148 "Red-breasted Nuthatch"</ref> | |
| Corsican nuthatch (Sitta whiteheadi) |
File:Sitta whiteheadi - Christoph Moning - 4 (cropped).jpeg | Template:Convert long, blue-grey above, and buff below. Male has a black crown and eye stripe separated by a white supercilium; the female has a grey crown and eye stripe. | Endemic to Corsica (c. 2,000 pairs)<ref name="HQcorsican">Harrap & Quinn (1996) pp. 133–135 "Corsican Nuthatch"</ref><ref>Template:Cite journal</ref> | |
| Chinese nuthatch (Sitta villosa) |
File:Sitta villosa - Kim, Hyun-tae (4) (cropped).jpg | Template:Convert long, greyish upper parts and pinkish underparts. | China, North Korea, and South Korea<ref name="HQchinese">Harrap & Quinn (1996) pp. 140–142 "Chinese Nuthatch"</ref> | |
| Western rock nuthatch (Sitta neumayer) |
File:Sitta neumayer - Western Rock Nuthatch, Mersin 2016-11-20 06-1.jpg | Template:Convert long. white throat and underparts shading to buff on the belly. The shade of grey upper parts and the darkness of the eye stripe vary between the three subspecies. | The Balkans east through Greece and Turkey to Iran (130,000)<ref name="HQwrock">Harrap & Quinn (1996) pp. 155–158 "Western Rock Nuthatch"</ref> | |
| Eastern rock nuthatch (Sitta tephronota) |
File:Tahtseyok.jpg | Template:Convert long, greyish upper parts and whitish underparts, pinkish rump. | Northern Iraq Kurdistan and western Iran east through Central Asia (43,000–100,000 in Europe)<ref name="HQerock">Harrap & Quinn (1996) pp. 158–161 "Eastern Rock Nuthatch"</ref> | |
| Siberian nuthatch (Sitta arctica) |
File:Sitta arctica png.png | Template:Convert long, long and thin bill, black eye stripe, blue-grey upper parts, pure white underparts, long claw. | Eastern Siberia | |
| White-browed nuthatch (Sitta victoriae) |
File:2M3A6919 - White-browed Nuthatch - Sitta victoriae (cropped).jpg | Template:Convert long, greyish upper parts and mostly whitish underparts. | Endemic to Myanmar<ref name="HQwbn1">Harrap & Quinn (1996) pp. 125–126 "White-browed Nuthatch"</ref> | |
| White-tailed nuthatch (Sitta himalayensis) |
File:White-tailed Nuthatch Sitta himalayensis perches on a branch, India 2016.jpg | Template:Convert long, smaller bill than S. cashmirensis, rufous-orange underparts with unmarked bright rufous undertail-coverts, white on the upper tail coverts is difficult to see in the field. | Himalayas from northeast India to southwest China, locally east to Vietnam<ref name="HQwtn">Harrap & Quinn (1996) pp. 123–125 "White-tailed Nuthatch"</ref> | |
| Eurasian nuthatch (Sitta europaea) |
File:Eurasian Nuthatch (Sitta europaea) -modified.jpg | Template:Convert long, black eye stripe, blue-grey upper parts, reddish and/or white underparts depending on subspecies. | Temperate Eurasia (10 million)<ref name="HQeurasian"/> | |
| Chestnut-vented nuthatch (Sitta nagaensis) |
File:Chestnut-vented nuthatch (cropped).jpg | Template:Convert long, mostly pale grey upper parts and mostly whitish underparts, dark eye stripe. | Northeast India east to northwest Thailand<ref name="HQcvn">Harrap & Quinn (1996) pp. 114–117 "Chestnut-vented Nuthatch"</ref> | |
| Kashmir nuthatch (Sitta cashmirensis) |
File:Kashmir Nuthatch (Sitta cashmirensis) (48553160711) (cropped).jpg | Template:Convert long, mostly greyish upper parts, reddish underparts with a paler throat and chin. | Eastern Afghanistan to western Nepal<ref name="HQkashmir">Harrap & Quinn (1996) pp. 117–119 "Kashmir Nuthatch"</ref> | |
| Indian nuthatch (Sitta castanea) |
File:Chestnut-bellied Nuthatch.jpg | Template:Convert long. | Northern and central India<ref name="Rasmussen" /><ref name="HQcbn" /> | |
| Chestnut-bellied nuthatch (Sitta cinnamoventris) |
File:Chestnut-bellied Nuthatch Ghatgarh Uttarakhand India 03.12.2014.jpg | Template:Convert long, colours vary between the subspecies. | Foothills of the Himalayas from northeast India to western Yunnan and Thailand<ref name="Rasmussen"/><ref name="HQcbn">Harrap & Quinn (1996) pp. 119–123 "Chestnut-bellied Nuthatch"</ref> | |
| Burmese nuthatch (Sitta neglecta) |
File:Sitta neglecta.svg | Template:Convert long. | Myanmar to Laos, Cambodia and southern Vietnam<ref name="Rasmussen"/><ref name="HQcbn"/> | |
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Distribution and habitatEdit
Members of the nuthatch family live in most of North America and Europe and throughout Asia down to the Wallace Line. Nuthatches are sparsely represented in Africa; one species lives in a small area of northeastern Algeria<ref name="BWP1400">Snow & Perrins (1998) pp. 1400–1401 "Algerian Nuthatch"</ref> and a population of the Eurasian nuthatch subspecies, S. e. hispaniensis, lives in the mountains of Morocco.<ref name="BWP1402">Snow & Perrins (1998) pp. 1402–1404 "Nuthatch"</ref> Most species are resident year-round. The only significant migrant is the red-breasted nuthatch, which winters widely across North America, deserting the northernmost parts of its breeding range in Canada; it has been recorded as a vagrant in Bermuda, Iceland and England.<ref name="HQrbn"/>
Most nuthatches are woodland birds and the majority are found in coniferous or other evergreen forests, although each species has a preference for a particular tree type. The strength of the association varies from the Corsican nuthatch, which is closely linked with Corsican pine, to the catholic habitat of the Eurasian nuthatch, which prefers deciduous or mixed woods but breeds in coniferous forests in the north of its extensive range.<ref name="BWP1402"/><ref name="BWP1399">Snow & Perrins (1998) pp. 1399–1400 "Corsican nuthatch"</ref> However, the two species of rock nuthatches are not strongly tied to woodlands: they breed on rocky slopes or cliffs, although both move into wooded areas when not breeding.<ref name="BWP1404">Snow & Perrins (1998) pp. 1404–1406 "Eastern Rock Nuthatch"</ref><ref name = "BWP1406"/> In parts of Asia where several species occur in the same geographic region, there is often an altitudinal separation in their preferred habitats.<ref>Template:Cite journal</ref><ref>Template:Cite journal</ref>
Nuthatches prefer a fairly temperate climate; northern species live near sea level whereas those further south are found in cooler highland habitats. Eurasian and red-breasted nuthatches are lowland birds in the north of their extensive ranges, but breed in the mountains further south; for example, the Eurasian nuthatch, which breeds where the July temperature range is Template:Convert, is found near sea level in Northern Europe, but between Template:Convert altitude in Morocco.<ref name="BWP1402"/> The velvet-fronted nuthatch is the sole member of the family which prefers tropical lowland forests.<ref name="HQvfn"/>
BehaviourEdit
Nesting, breeding and survivalEdit
All nuthatches nest in cavities; except for the two species of rock nuthatches, all use tree holes, making a simple cup lined with soft materials on which to rest eggs. In some species the lining consists of small woody objects such as bark flakes and seed husks, while in others it includes the moss, grass, hair and feathers typical of passerine birds.<ref name="HQeurasian"/><ref name="HQpigmy"/>
Members of the red-breasted nuthatch superspecies excavate their own tree holes, although most other nuthatches use natural holes or old woodpecker nests. Several species reduce the size of the entrance hole and seal up cracks with mud. The red-breasted nuthatch makes the nest secure by daubing sticky conifer resin globules around the entrance, the male applying the resin outside and the female inside. The resin may deter predators or competitors (the resident birds avoid the resin by diving straight through the entrance hole).<ref name="Cornellrbn">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> The white-breasted nuthatch smears blister beetles around the entrance to its nest, and it has been suggested that the unpleasant smell from the crushed insects deters squirrels, its chief competitor for natural tree cavities.<ref name="Kilham">Template:Cite journal</ref>
The western rock nuthatch builds an elaborate flask-shaped nest from mud, dung and hair or feathers, and decorates the nest's exterior and nearby crevices with feathers and insect wings. The nests are located in rock crevices, in caves, under cliff overhangs or on buildings.<ref name="HQwrock"/> The eastern rock nuthatch builds a similar but less complex structure across the entrance to a cavity. Its nest can be quite small but may weigh up to 32 kg (70 lb). This species will also nest in river banks or tree holes and will enlarge its nest hole if it the cavity is too small.<ref name="HQerock"/>
Nuthatches are monogamous. The female produces eggs that are white with red or yellow markings; the clutch size varies, tending to be larger for northern species. The eggs are incubated for 12 to 18 days by the female alone, or by both parents, depending on the species. The altricial (naked and helpless) chicks take between 21 and 27 days to fledge.<ref name="HQerock"/><ref name="BWP1406">Snow & Perrins (1998) pp. 1406–1407 "Rock Nuthatch"</ref><ref name="BWPintro">Snow & Perrins (1998) p. 1398 "Nuthatch: Family Sittidae"</ref><ref name="Matthysen & Löhrl">Template:Cite book</ref> Both parents feed the young, and in the case of two American species, brown-headed and pygmy, helper males from the previous brood may assist the parents in feeding.<ref name="ADWpygmy"/><ref name="Cornellbhn">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
For the few species on which data are available, the average nuthatch lifespan in the wild is between 2 and 3.5 years, although ages of up to 10 years have been recorded.<ref name="ADWpygmy">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref name="ADWwbn">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> The Eurasian nuthatch has an adult annual survival rate of 53%<ref name="BTO">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> and the male Corsican nuthatch 61.6%.<ref name="Thibault">Template:Cite journal</ref> Nuthatches and other small woodland birds share the same predators: accipiters, owls, squirrels and woodpeckers. An American study showed that nuthatch responses to predators may be linked to reproductive strategies. It measured the willingness of males of two species to feed incubating females on the nest when presented with models of a sharp-shinned hawk, which hunts adult nuthatches, or a house wren, which destroys eggs. The white-breasted nuthatch is shorter-lived than the red-breasted nuthatch, but has more young, and was found to respond more strongly to the egg predator, whereas the red-breasted showed greater concern with the hawk. This supports the theory that longer-lived species benefit from adult survival and future breeding opportunities while birds with shorter life spans place more value on the survival of their larger broods.<ref name="Ghalambor">Template:Cite journal</ref>
Cold can be a problem for small birds that do not migrate. Communal roosting in tight huddles can help conserve heat and several nuthatch species employ it—up to 170 pygmy nuthatches have been seen in a single roost. The pygmy nuthatch is able to lower its body temperature when roosting, conserving energy through hypothermia and a lowered metabolic rate.<ref name="ADWpygmy"/>
FeedingEdit
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Nuthatches forage along tree trunks and branches and are members of the same feeding guild as woodpeckers. Unlike woodpeckers and treecreepers, however, they do not use their tails for additional support, relying instead on their strong legs and feet to progress in jerky hops.<ref name="Matthysen & Löhrl"/><ref>Template:Cite journal</ref> They are able to descend head-first and hang upside-down beneath twigs and branches. Krüper's nuthatch can even stretch downward from an upside-down position to drink water from leaves without touching the ground.<ref name="Albayrak">Template:Cite journal</ref> Rock nuthatches forage with a similar technique to the woodland species, but seek food on rock faces and sometimes buildings. When breeding, a pair of nuthatches will only feed within their territory, but at other times will associate with passing tits or join mixed-species feeding flocks.<ref name="HQfamily"/><ref name="BWPintro"/><ref name="Robson">Template:Cite book</ref>
Insects and other invertebrates are a major portion of the nuthatch diet, especially during the breeding season, when they rely almost exclusively on live prey,<ref name="ADWwbn"/> but most species also eat seeds during the winter, when invertebrates are less readily available. Larger food items, such as big insects, snails, acorns or seeds may be wedged into cracks and pounded with the bird's strong bill.<ref name="HQfamily"/> Unusually for a bird, the brown-headed nuthatch uses a piece of tree bark as a lever to pry up other bark flakes to look for food; the bark tool may then be carried from tree to tree or used to cover a seed cache.<ref name="Cornellbhn"/>
All nuthatches appear to store food, especially seeds, in tree crevices, in the ground, under small stones, or behind bark flakes, and these caches are remembered for as long as 30 days.<ref name="HQeurasian"/><ref name="HQpigmy"/><ref>Template:Cite journal</ref> Similarly, the rock nuthatches wedge snails into suitable crevices for consumption in times of need.<ref name="HQwrock"/><ref name="HQerock"/> European nuthatches have been found to avoid using their caches during benign conditions in order to save them for harsher times.<ref>Template:Cite journal</ref>
Conservation statusEdit
Some nuthatches, such as the Eurasian nuthatch and the North American species, have extensive ranges and large populations, and few conservation problems,<ref name="Birdlife">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> although locally they may be affected by woodland fragmentation.<ref name="Varo"/><ref name="vanLangeveld">Template:Cite journal</ref> In contrast, some of the more restricted species face severe pressures.
The endangered white-browed nuthatch is found only in the Mount Victoria area of Burma, where forest up to Template:Convert above sea level has been almost totally cleared and habitat between Template:Convert is heavily degraded. Nearly 12,000 people live in the Natma Taung national park which includes Mount Victoria, and their fires and traps add to the pressure on the nuthatch. The population of the white-browed nuthatch, estimated at only a few thousand, is decreasing, and no conservation measures are in place.<ref>Template:Cite iucn</ref><ref name="ThetZawNaing">Template:Cite journal</ref> The Algerian nuthatch is found in only four areas of Algeria, and it is possible that the total population does not exceed 1,000 birds. Fire, erosion, and grazing and disturbance by livestock have reduced the quality of the habitat, despite its location in the Taza National Park.<ref name="Sittaledanti">Template:Cite iucn</ref>
Deforestation has also caused population declines for the vulnerable Yunnan and yellow-billed nuthatches. The Yunnan nuthatch can cope with some tree loss, since it prefers open pine woodland, but although still locally common, it has disappeared from several of the areas in which it was recorded in the early 20th century.<ref>Template:Cite iucn</ref> The threat to yellow-billed is particularly acute on Hainan, where more than 70% of the woodland has been lost in the past 50 years due to shifting cultivation and the use of wood for fuel during Chinese government re-settlement programmes.<ref>Template:Cite iucn</ref>
Krüper's nuthatch is threatened by urbanisation and development in and around mature coniferous forests, particularly in the Mediterranean coastal areas where the species was once numerous. A law promoting tourism came into force in Turkey in 2003, further exacerbating the threats to their habitat. The law reduced bureaucracy and made it easier for developers to build tourism facilities and summer houses in the coastal zone where woodland loss is a growing problem for the nuthatch.<ref name="Sittakrueperi">Template:Cite iucn</ref><ref name=Turkey>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
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External linksEdit
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